Exhaust from combustion engines creates nitrogen oxide (NOx) that contributes to smog and other forms of environmental pollution. NOx should be removed from the exhaust streams of these engines in order to protect the environment and satisfy government regulations. Current 3-way catalyst converter technology may be used to remove NOx in automotive exhaust under certain limiting conditions. For example, 3-way catalysts operate at high temperatures greater than 300 degrees C. In addition, in order to meet current emissions standards, 3-way catalysts contain a large quantity of precious metals such as platinum, rhodium, and palladium. Further, prior art catalysts may have difficulty in reacting with NOx in the presence of oxygen.
There is therefore a need in the art for an improved catalyst that reduces NOx under various conditions including oxygen rich and oxygen deficient conditions. There is also a need for a catalyst that does not include expensive precious metals and is economical to manufacture. There is a further need in the art for a catalyst that includes a surface that selectively interacts with NOx in the presence of oxygen or in the absence of oxygen. There is also a need in the art for a process for reducing NOx in various conditions including oxygen rich and oxygen deficient conditions.